Question: Suppose the area of a circle is ${64\pi}$. What is its diameter?
Explanation: ${K = 64\pi}$ ${d = 16}$ First, find the radius: $K = \pi r^2$ , so $r = \sqrt{K / \pi} = \sqrt{{64\pi} / \pi} = {8}$ Now find the diameter: $d = 2r = 2\cdot {8} = {16}$.